Leptin, like insulin, is an important regulator of weight and metabolism in humans. The precise role of A-100 in diabetes is not well understood.Clinical trials have shown that A-100 is safe and tolerated. The primary objective of this randomized, double-blind, placebo-controlled study to assess changes in glycemic control associated with subcutaneously injected A-100 (the recombinant form of the hormone, leptin) in overweight subjects with Type II Diabetes who are on stable doses of insulin alone or insulin and a sulfonylurea. Secondary objectives are to assess changes in body weight, body composition, anthropometrics, and health related quality of life. Changes in insulin and sulfonylurea requirements for glucose control will be assessed. Safety and tolerability will also be determined.